The invention relates to a method of setting blind rivets provided with cylindrical, continuous hollow spaces, preferably for connecting structural parts which are accessible only on one side and are provided with bores in alignment with one another, the blind rivet being placed in such a way onto a riveting mandrel having a thickened end, the diameter of which, at least in one dimension, is larger than the diameter of the rivet hollow space, that the rivet head rests on the side remote from the thickened end, the rivet then being inserted, together with the riveting mandrel, into the structural part bores, in alignment with one another, until the rivet head rests on the surface of the outer structural part, the rivet head then being supported by a holding-down part and finally the riveting mandrel, for opening out the rivet end projecting through the bores, being moved against the pressure direction of the holding-down part, and also a device for implementing this method.
Blind riveting methods are used for riveting structures which are accessible only from one side, for example in coach work and small tank construction in the case of double-shell methods of construction and the like.
In a known blind riveting method of the above-mentioned type, a blind rivet is used with an inserted riveting mandrel. In this method, the thickened end of the riveting mandrel lies directly in front of the free rivet end to be opened out and the mandrel is provided with a predetermined breaking point at a distance from the thickened end. On the head side of the rivet, the riveting mandrel projects a short length out of the rivet hollow space. The blind rivet is set by means of manual riveting tongs or a compressed-air-actuated riveting tool by the holding-down part being pressed onto the head of the inserted rivet and the riveting mandrel being acted upon by a tensile force in the direction out of the rivet hollow space. When a certain tensile force is applied, the free rivet end is opened out and, once the opening-out operation has been carried out, the riveting mandrel breaks off at the predetermined breaking point. Whereas the riveting mandrel part provided with the thickened end remains in the opened-out end of the blind rivet, or falls off inwards, the riveting mandrel part sitting in the riveting tool is removed and thrown away.
Although this known riveting method is very reliable, it is relatively expensive because all of the rivets have to be provided with a riveting mandrel which, after execution of the operation, is a scrap product.